The invention relates to a motor vehicle navigation system.
Navigation systems are known which automatically compute a route to be traveled, as a function of a starting position or an actual position, of selected route criteria (fast, short, expressway preferred, . . . ), and of a destination.
For example, before an intersection is reached at which, corresponding to the route, a turn to the right has to be made, the driving maneuver information “please turn to the right in 300 meters” is determined as a function of the actual position and the route to be traveled and is acoustically emitted by way of a corresponding output device, for example, by use of synthetized language.
Such acoustically emitted driving maneuver information may be extremely disturbing to a driver, especially in the city and on routes known per se. However, a deactivation of the acoustic output may, for example, later on in the route, have the result that an important expressway exit ramp is missed, which may lead to a long detour.
It is now an object of the invention to provide a motor vehicle navigation system by which a user is acoustically informed concerning imminent driving maneuvers according to specified requirements.
This object is achieved by a motor vehicle navigation system and method of operating same having an output device for the acoustic output of driving maneuver information. A processor device is equipped such that a route to be traveled is determined. Driving maneuver information is determined based on the route to be traveled and on the actual position. At least one alternate route is computed, assuming that the determined driving maneuver information is not observed and, as a function of the difference between the route and the alternate route, particularly with respect to at least one of an expected driving time, driving distance and driving cost, a determination is made whether or not to acoustically emit driving maneuver information. Advantageous further developments of the invention are described herein.
The invention thus automatically emits driving maneuver information acoustically only when its non-observance would, for example, result in a large detour or in a considerable prolongation of the driving time.
A motor vehicle navigation system according to the invention has an output device for the acoustic output of driving maneuver information and a processor device which is equipped such that a route to be traveled is determined. Based on the route to be traveled and the actual position, in particular, for the street or road junction to be traveled next (intersection, branching-Off, exit ramp, entrance ramp, . . . ), driving maneuver information (or an imminent driving maneuver) is determined. At least one alternate route, particularly to the same driving destination and/or while assuming the same route criteria, is computed, assuming that the determined driving maneuver information is not observed (or the determined driving maneuver is not carried out). As a function of the difference between the route and the alternate route, particularly with respect to the expected driving time, the driving distance and/or the driving cost, the driving maneuver information (or information concerning the determined driving maneuver) is either acoustically emitted or not.
In this case, the alternate route may or may not contain reversing maneuvers or turning maneuvers. In addition or as an alternative, the difference between the route and the alternate route may also relate to the distance of the route or the alternate route from at least one point of interest (gas station, museum, etc. . . . ).
If the road junction of concern is an exit ramp, as a rule, the computation of one alternate route will be sufficient. In the case of other streets or road junctions, the determination of several alternate routes may be advantageous. As required, in addition to the route and the alternate route, additional routes are therefore computed, which may result from the non-observance of the driving maneuver information, particularly for the street or road junction to be traveled next. For example, when approaching an intersection of two roads, in addition to the route which, for example, indicates a turning-off to the left, a first alternate route may be computed, in the case of which it is assumed that the vehicle will turn to the right, and a second alternate route may be computed, in the case of which it is assumed that the vehicle will drive straight ahead. Then, preferably the differences are determined between the route and the alternate routes, particularly with respect to the expected driving time, driving distance and/or driving cost, and the thereby determined maximal difference is used as a condition for the decision as to whether the driving maneuver information (or information concerning the determined driving maneuver) (“please turn to the left”) is either acoustically emitted or not.
As a result, it is achieved that, when the motor vehicle navigation system is correspondingly adjusted, a driver will be disturbed only by the acoustic output of that driving maneuver information whose non-observance would result in a considerable increase of the driving distance or driving time, such as may occur if an exit ramp is missed.
According to an embodiment of the invention, it is provided that a straight-ahead driving maneuver, particularly on the expressway or before an exit ramp, is not considered to be a driving maneuver within the scope of the invention, and/or that corresponding driving maneuver information is basically not emitted within the scope of the invention, particularly on an expressway or before an exit ramp. Particularly on an expressway or before an exit ramp, preferably no alternate route and/or no difference will then be computed and/or no acoustic driving maneuver information will then be emitted, if the driving maneuver is the “straight-ahead” route.
It is preferably provided that driving maneuver information will be acoustically emitted when the difference between the route and the alternate route exceeds a predetermined limit value, particularly with respect to the expected driving time, driving distance and/or driving cost.
As an alternative or in addition, it is provided that driving maneuver information will not be acoustically emitted when the difference between the route and the alternate route does not exceed a predefined limit value, particularly with respect to the expected driving time and/or driving distance.
In addition, particularly preferably, an output device for the visual output of driving maneuver information is provided, the driving maneuver information being emitted independently of the difference between the route and the alternate route, particularly with respect to the expected driving time, driving distance and/or driving cost. A driver will thereby be definitely informed in a visual manner concerning imminent driving maneuvers. This manner of output is not as disturbing as the acoustic output.
Advantageously, an operator can adjust the limit value by use of an adjusting device in order to adapt the automatic suppression of the acoustic output to the user's needs.
A preferred further development of the invention provides that, as a function of the respective difference between the route and the alternate route, particularly with respect to the expected driving time, driving distance and/or driving cost, the driving maneuver information is divided into different driving maneuver information classes, and that driving maneuver information is either acoustically emitted or not as a function of its driving maneuver information class.
At least one driving maneuver information class, whose pertaining driving maneuver information is either to be acoustically emitted or not, can preferably be selected by an operator by use of a selecting device.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of one or more preferred embodiments when considered in conjunction with the accompanying drawings.